Modular fiber optic cassette, system and method

ABSTRACT

A fiber optic cassette system is disclosed comprising a case defining a tray receiving space and an opening to a space, a tray received within the case for movement between a stored position wherein the tray is inside the case and an accessible position wherein a front end of the tray is in front of the opening and outside of the case, fiber optic cassettes arrangeable side by side along the tray front end, a first of the cassettes comprising a width of one of one, two, three, four or six standard width units and a second of the cassettes comprising a width different from the first cassette width and one of one, two, three, four or six standard width units, and a fastener for removeably the cassettes to the tray. When arranged on the tray each of said selected cassettes is directly adjacent at least one other selected cassette.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/143,831 filed on Sep. 27, 2018 and claimspriority under 35 USC § 119(e) of U.S. provisional application Ser. No.62/567,339 filed on Oct. 3, 2017 which is incorporated herein in itsentirely by reference.

FIELD OF THE INVENTION

The present invention relates to a modular fiber optic cassette, systemand method. In particular, the present invention relates to a fiberoptic cassette comprising a width of one or more standard width unitsand such that fiber optic cassettes of different widths can be arrangedon the same tray while optimizing the use of tray space.

BACKGROUND OF THE INVENTION

The prior art discloses fiber optic cassettes or splice boxes for use interminating fiber optic trunk cables and splitting them out to patchcables which are removeably arranged on tray systems within a rackmounted case. One drawback of these cassettes and tray systems is thatthey are typically preconfigured to terminate fiber optic cablescomprising a single predetermined number of optic fibers. Anotherdrawback is that cassettes which are used to terminate fiber opticcables comprising different numbers of optic fibers are generallyincompatible with one another and additionally require trays withdifferent spacing, securing mechanisms and the like.

SUMMARY OF THE INVENTION

In order to address the above and other drawbacks there is provided amodular fiber optic cassette system. The system comprises a casecomprising a top and a bottom wall and two opposed side walls, each ofthe sidewalls attached between respective side edges of the top andbottom wall, the walls together defining a tray receiving space therebetween and a forward edge of each the wall together defining an openingto the tray receiving space, at least one tray slideably received withinthe tray receiving space for movement between a stored position whereinthe tray is completely inside the tray receiving space and an accessibleposition wherein a front end of the tray is in front of the opening andoutside of the tray receiving space, a set of fiber optic cassettes, aselected plurality of the cassettes arrangeable side by side along thetray front end wherein each of the cassettes comprises a plurality ofoptic plug receiving receptacles arranged side by side in a row along afront thereof, a first of the set of cassettes comprising a firstcassette width of one of one, two, three, four and six standard widthunits and a second of the cassettes comprising a second cassette widthdifferent from the first cassette width and one of one, two, three, fourand six standard width units, and a fastener for removeably securingeach of the cassettes to the tray. When arranged on the tray each ofsaid selected cassettes is directly adjacent at least one other selectedcassette.

Additionally, there is provided a method for organising a traycomprising a front edge in a fiber optic interconnect system. The methodcomprises defining a standard width unit wherein a width of the frontedge is substantially evenly divisible by the standard width unit,selecting a plurality of cassettes for installation on the tray from aset of cassettes having a plurality of different widths, wherein each ofthe different widths is evenly divisible by the standard width unit, andreleasably securing the selected cassettes along the front edge of thetray. When arranged on the tray each of said selected cassettes isdirectly adjacent at least one other selected cassette.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a right front perspective view of a modular fiber opticcassette and system mounted in a rack and in accordance with anillustrative embodiment of the present invention;

FIGS. 2A and 2B provide respectively a raised right front perspectiveview and a lowered right front perspective view of a modular fiber opticcassette in accordance with an illustrative embodiment of the presentinvention;

FIG. 3 provides a front plan view of a modular fiber optic cassettesystem mounted in a rack in accordance with an illustrative embodimentof the present invention;

FIGS. 4A through 4D provide raised right front perspective views of atray populated with respectively six (6), four (4), three (3) and two(2) cassettes of different widths;

FIGS. 5A, 5B and 5C provide front plan views of a modular fiber opticcassette and system mounted in a rack respectively in accordance withfirst, second and third alternative embodiments of the presentinvention;

FIGS. 6A and 6B provide respectively a raised right front perspectiveview and a lowered right front perspective view of a modular fiber opticcassette in accordance with an alternative illustrative embodiment ofthe present invention; and

FIGS. 7A and 7B provide respectively a raised right front perspectiveview of a tray comprising a plurality modular fiber optic cassettes anda pair of cable management brackets and lowered right front perspectiveview of a cable management bracket in accordance with a secondalternative illustrative embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring now to FIG. 1, a modular cassette system, generally referredto using the reference numeral 10, will now be described. The modularcassette comprises a slideable tray 12 illustratively mounted within acase 14. The case 14 comprises a top wall 16, a bottom wall 18 and apair of opposed side walls 20 defining a tray receiving space 22therebetween. The case 14 is illustratively mounted to the rails 24 of arack via a pair of mounting brackets 26 wherein one of the brackets 26is attached to an outer surface 28 of a respective one of the sidewalls20. The front edges 30 of the walls 16, 18, 20 define an opening viawhich the tray receiving space 22 can be accessed. In a particularillustrated embodiment the system 10 is shown for mounting in a 19″rack, however in a particular embodiment the system 10, with suitablemodifications, may be mounted equally in a cross connect system, fiberbay or wall mount or the like.

Referring to FIGS. 2A and 2B in addition to FIG. 1, the tray 12 receivesa plurality of removable fiber optic module or cassettes 32 arrangedside by side on an upper surface 34 thereof. In a first embodiment eachfiber optic cassette 32 is secured to the tray 12 using a fastenercomprising tabs 36 of inverted “T” cross section which engage withrespective slots 38 machined or otherwise formed in the tray 12. Aflexible tab 40 is also provided which comprises a boss 42 that engagesa respective aperture 44 machined or otherwise formed in the tray 12when the tabs 36 are engaged within their respective slots 38, therebyreleasably securing the cassette 32 to the tray 12. In order to betterorient the cassette 36 on the tray during installation, the tray 12comprises a raised shoulder 46 which is received within a channel 48moulded or otherwise formed in an underside 50 of the cassette 32.

Still referring to FIGS. 2A and 2B, each cassette 32 illustrativelycomprises a plurality of receptacle modules 52 each comprising aplurality of receptacles 54, illustratively LC Quad type receptacles,arranged in a row and exposed along a forward edge 56 of the cassette32. The cassette 32 also illustratively terminates a fiber optic cable58, such as a trunk cable or the like, comprising a plurality of opticfibers at a multi-fiber connector receiving receptacle 60 on a rearwardedge. Each optic fiber of the fiber optic cable 58 is interconnectedwith a respective one of the receptacles 54 using an optic fiber segment62 comprising a receptacle end which is terminated by a plug 64. Thesegments 62, which are typically longer than the distance between theforward edge and the rearward edge, are typically looped several timeswithin the cassette 32, for example in a serpentine or the like. Aperson of ordinary skill in the art will understand that an optic fiberterminated with a plug (not shown) inserted into a selected one of thereceptacles 54 will interconnect the optic fiber with a selected opticfiber segment 62.

Referring now to FIG. 3 and FIGS. 4A through 4D, as discussed above,each cassette 32 illustratively comprises a plurality of receptaclemodules 52 each comprising four (4) receptacles 54. It is foreseen toprovide a set of four (4) different cassette sizes to accommodateterminating fiber optic cables comprising different number of opticfibers. Each of the different cassette sizes of the set is based on aninteger multiple of a standardised pitch or width unit W wherein onestandardized width unit accommodates a single receptacle module 52comprising four (4) receptacles 54. Illustratively, a 2W cassette 32comprising two (2) modules 52 accommodating eight (8) optic fibers (FIG.4A) is provided, a 3W cassette 32 comprising three (3) modules 52accommodating twelve (12) optic fibers (FIG. 4B) is provided, a 4Wcassette 32 comprising four (4) modules 52 accommodating sixteen (16)optic fibers (FIG. 4C) is provided and a 6W cassette 32 comprising six(6) modules 52 accommodating twenty-four (24) optic fibers (FIG. 4D) isprovided for. The 2W, 3W, 4W and 6W cassettes 32 are typically used onlywith like cassettes 32 as illustrated and such that respectively six(6), four (4), three (3) and two (2) cassettes fit snuggly side by sideon the 12W tray, although in a particular embodiment cassettes 32 ofdifferent widths could be used together.

Although the present illustrative embodiment In a particular embodimentthe pitch/width W is based on a LC Quad (SC Duplex) technology footprintcomprising four (4) connectors, in an alternative embodiment thepitch/width W could be based on a different technology footprint,including SC Duplex comprising two (2) connectors and MPO typeconnectors comprising inter alia multiple optic fibers such as MPO-12,MPO-16 and MPO-24.

Still referring to FIGS. 3, 4A through 4D in addition to FIG. 1, aperson of ordinary skill in the art will now understand that thedisclosed system of cassettes 32 can be used to accommodate optic fibercables 58 comprising different numbers of optic fibers 62 while ensuringthat the same number of optic fibers 62 are accessible via the exposedreceptacles 54.

Referring back to FIG. 1, the spacing between adjacent slots 38 as wellas the spacing between adjacent apertures 44 conforms to thestandardised width unit W and such that the 2W, 3W, 4W and 6W cassettes32 can be readily accommodated on the tray.

Referring now to FIG. 5A, in a first alternative embodiment of thesystem each receptacle modules 52 comprises a duplex type modulearranged vertically. Additionally in a first cassette size four (4) ofsuch duplex modules 52 are provided to provide for eight (8) receptacles54 for terminating a fiber optic cable (not shown) comprised of eight(8) optic fibers. Similar to the first embodiment discussed above, sizesfor twelve (12), sixteen (16) and twenty four (24) receptacles are alsoprovided. Again, as the width of the cassettes is an integer multiple ofthe same pitch/width, cassettes of different widths can be used in thesame tray system or in some cases on the same tray without modificationor changing the density of the receptacles 54 for terminating opticfibres.

Referring now to FIG. 5B, in a second alternative embodiment of thesystem each receptacle modules 52 comprises a Quad type module arrangedvertically. In a first cassette size two (2) of such quad modules 52 areprovided to provide for eight (8) receptacles 54 for terminating a fiberoptic cable (not shown) comprised of eight (8) optic fibers. Cassettescomprising three (3), four (4) and six (6) quad type modules 52 areprovided to provide respectively twelve (12), sixteen (16) andtwenty-four (24) receptacles. Again, as the width of the cassettes is aninteger multiple of the same pitch/width, cassettes of different widthscan be used in the same tray system or in some cases on the same traywithout modification or changing the density of the receptacles 54 forterminating optic fibres.

Referring now to FIG. 5C, in a third alternative embodiment of thesystem each receptacle modules 52 comprises a duplex type modulearranged horizontally in two rows. In a first cassette size four (4) ofsuch duplex modules 52 are provided to provide for eight (8) receptacles54 for terminating a fiber optic cable (not shown) comprised of eight(8) optic fibers. Cassettes comprising six (6), eight (8) and twelve(12) duplex type modules 52 are provided to provide respectively twelve(12), sixteen (16) and twenty-four (24) receptacles. Again, as the widthof the cassettes is an integer multiple of the same pitch/width,cassettes of different widths can be used in the same tray system or insome cases on the same tray without modification or changing the densityof the receptacles 54 for terminating optic fibres.

Referring now to FIGS. 6A and 6B in addition to FIG. 1, in analternative embodiment of an assembly for securing the cassettes 32 tothe tray 12 the tray 12 is manufactured from a ferrous material such assteel or the like and the fastener comprises a magnet 66 which isattracted to the tray and embedded or otherwise secured within a recess68 formed in the underside 50 of the cassette 32. The tray 12, furthercomprises a series of spaced slots 70 arranged along the raised shoulder46 which engage bosses 72 to ensure correct positioning of the cassettes32 on the tray 12.

Referring now to FIG. 7A in a second alternative illustrative embodimentother equipment, such as a cable management bracket 74 can be providedwith the same width W and such that they can be mounted to together withthe cassettes 32 to the tray 12. In this regard, and with reference toFIG. 7B in addition to FIG. 7, the cable management bracket 74 isprovided with tabs 76 comprising an inverted “T” cross section whichengage with engage a slot 38 on the tray 12. A flexible tab 78 isprovided which comprises a boss 80 that engages one of the apertures 44in the tray 12 when the tab 76 is engaged within its respective slot 38,thereby releasable securing the cable management bracket 74 to the tray12. In order to better orient the cable management bracket 74 on thetray during installation, the raised shoulder 46 of the tray 12 isreceived within a channel 82 moulded or otherwise formed in theunderside 84 of the cable management bracket 74. Additionally, eachcable management bracket 74 includes a cable management loop 86 forreceiving a plurality of optic fibres (not shown) which are terminatedat respective ones of the receptacles 54. A flexible strip 88 across themouth of the cable management loop 86 is provided to releasably retainthe plurality of optic fibers within the loop 86.

Although the present invention has been described hereinabove by way ofspecific embodiments thereof, it can be modified, without departing fromthe spirit and nature of the subject invention as defined in theappended claims.

1. A modular fiber optic cassette system, the system comprising: a casecomprising a top and a bottom wall and two opposed side walls, each ofsaid sidewalls attached between respective side edges of said top andbottom wall, said walls together defining a tray receiving space therebetween and a forward edge of each said wall together defining anopening to said tray receiving space; at least one tray slideablyreceived within said tray receiving space for movement between a storedposition wherein said tray is completely inside said tray receivingspace and an accessible position wherein a front end of said tray is infront of said opening and outside of said tray receiving space; a set offiber optic cassettes, a selected plurality of the cassettes arrangeableside by side along said tray front end wherein each of said cassettescomprises a plurality of optic plug receiving receptacles arranged sideby side in a row along a front thereof, a first of said set of cassettescomprising a first cassette width of one of one, two, three, four andsix standard width units and a second of said cassettes comprising asecond cassette width different from said first cassette width and oneof one, two, three, four and six standard width units; and a fastenerfor removeably securing each of said cassettes to said tray wherein whenarranged on the tray each of said selected cassettes is directlyadjacent at least one other selected cassette.
 2. The modular fiberoptic cassette system of claim 1, wherein said tray has a widthdimensioned to receive at least twelve standard width units side byside.
 3. The modular fiber optic cassette system of claim 1, whereineach of said cassettes comprises a multi fiber connector receivingreceptacle arranged on a rear thereof and a plurality of optic fibers,one of said optic fibers interconnecting a respective one of said opticplug receiving receptacles with said multi fiber connector receivingreceptacle.
 4. The modular fiber optic cassette system of claim 1,wherein each of said cassettes comprises four fiber optic plug receivingreceptacles arranged side by side in a row along a front thereof foreach standard width unit.
 5. The modular fiber optic cassette system ofclaim 1, wherein said system is for mounting in a rack and furthercomprising a pair of mounting brackets, one of said brackets attached toeach of said sidewalls on either side of an outside of said case, saidmounting brackets for securing said case to the rack.
 6. The modularfiber optic cassette system of claim 1, wherein said tray ismanufactured from a ferrous metal and said fastener comprises a magnet.7. The modular fiber optic cassette system of claim 1, furthercomprising at least one elongate cable management bracket comprising acable management loop and a fastener for removeably securing said atleast one bracket to said tray, said bracket having a bracket width ofone of said standard width units and further wherein when installed onsaid tray adjacent an installed one of said cassettes, said cablemanagement loop is positioned in front of and to a side of saidplurality of optic plug receiving receptacles of said installedcassette.
 8. A method for organising a tray comprising a front edge in afiber optic interconnect system, the method comprising: defining astandard width unit wherein a width of the front edge is substantiallyevenly divisible by said standard width unit; selecting a plurality ofcassettes for installation on the tray from a set of cassettes having aplurality of different widths, wherein each of said different widths isevenly divisible by said standard width unit; and releasably securingsaid selected cassettes along the front edge of the tray; wherein whenarranged on the tray each of said selected cassettes is directlyadjacent at least one other selected cassette.
 9. The method fororganising a tray of claim 8, wherein said set of cassettes comprisescassettes comprising widths of one, two, three, four and six standardwidth units.
 10. The method for organising a tray of claim 8, whereinsaid selected cassettes all comprise the same width.
 11. The method fororganising a tray of claim 8, wherein said selected cassettes comprise afirst cassette having a first width and a second cassette having asecond width different from said first width.
 12. The method fororganising a tray of claim 8, wherein the width of the front edge issubstantially evenly divisible by a maximum of twelve (12) of saidstandard width units.
 13. The method for organising a tray of claim 11,wherein said selected cassettes further comprise a third cassettecomprising a third width different from said first width and said secondwidth.